Forget Cramming, Start Dreaming! How Sleep Consistency Affects College Grades

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By exploring the profound relationship between sleep patterns and academic outcomes, this study offers an objective lens by utilizing wearable technology.

The research, which monitored 88 college students, unveils that superior academic performance is closely associated with better sleep quality, duration, and consistency, leading to assessments. The research also addresses the gender disparities in sleep and academic performance, presenting insightful conclusions.

student dreaming

Practical Applications

  • Education professionals can leverage these findings to emphasize the importance of consistent sleep for students rather than merely the night before an exam.
  • University health and wellness programs can integrate sleep education into curricula to foster better student well-being and potentially enhance academic results.
  • As wearable sleep technology becomes increasingly prevalent, educators and researchers can harness this trend for more accurate, objective data collection.

Key Facts

  • The study utilized Fitbit devices for objective data collection.
  • Encompassed a diverse group of 88 students from MIT's Introduction to Solid State Chemistry.
  • Contrary to popular belief, sleep metrics from the night before an exam showed no significant correlation with performance.
  • Overall sleep quality and consistency in the weeks leading up to an exam were strong indicators of academic success.
  • There exist gender differences in sleep patterns and their relationship with academic performance.

Research Performed

The study was anchored on the premise that while sleep is indispensable in cognitive function and academic performance, most existing literature relies on subjective self-reports.

Participants in the study were provided with a Fitbit Charge HR, which they were instructed to wear throughout the entire semester. This wearable device was chosen because it is capable of recording various metrics, one of the most important being sleep.

The Fitbit's algorithm was used to determine sleep quality, assigning a value between 0, indicating poor sleep quality, and 10, indicating excellent sleep quality. In addition to monitoring sleep, the students' academic achievements were assessed over the 14-week course.

This assessment was done through a series of academic tests, which included nine quizzes, three midterm examinations, and a final exam.


The core findings from the study include:

  1. Direct correlations between bedtime, wake-up time, and academic scores, with earlier times yielding higher scores.
  2. The average sleep duration across participants stood at 7 hours and 8 minutes.
  3. Positive correlations were observed between sleep duration, quality, and academic performance.
  4. Inconsistency in sleep duration negatively affected academic scores.
  5. No significant correlation between sleep metrics from the night before an exam and the respective scores.
  6. Sleep metrics from the weeks leading up to exams were pivotal for performance.
  7. Variance in overall student scores was about 24.44% due to sleep factors, with each metric (duration, quality, inconsistency) having distinct contributions.
  8. Gender-based observations showed females generally had better sleep quality and less inconsistency. However, gender-based academic performance differences were nullified when adjusting for Sleep Quality.


The study used Fitbit's proprietary algorithms to determine sleep quality, and while Fitbit devices have shown accuracy in estimating sleep stages, there's no published evidence confirming the validity of Fitbit’s 1~10 sleep quality scores.

Several factors, including stress, anxiety, motivation, personality traits, and gender roles, can influence sleep, and these weren't fully addressed in the study, making it challenging to establish a direct causal relationship between sleep and academic performance.

The research was conducted on a specific student population at MIT enrolled in a particular course, raising concerns about whether the findings can be generalized to other student groups or different classes.

The study's reliance on Fitbit Charge HR devices for tracking sleep and activity might introduce inaccuracies, as these consumer-grade devices might not be as precise as specialized research equipment.

A grading system at MIT, where freshmen are graded on a "Pass or No Record" basis, could have affected the motivation of some students to perform their best on later assessments, potentially skewing the results.

Due to funding constraints, the study was limited to the first 100 volunteers, which might introduce a selection bias as this sample might not represent the entire class.

Some participants didn't consistently wear their Fitbit devices, leading to missing data. Although this missing data was considered random and was deleted for analysis, it could still impact the study's results.


Authors: Kana Okano, Jakub R. Kaczmarzyk, Neha Dave, John D. E. Gabrieli & Jeffrey C. Grossman

Contact: Jeffrey C. Grossman at [email protected]

Image: The image is credited to PracticalPsychology

Original Research: Sleep quality, duration, and consistency are associated with better academic performance in college students by Kana Okano et al. npj Science Of Learning


In an in-depth exploration of sleep patterns vis-à-vis academic performance, this study deployed wearable activity trackers, monitoring 88 college students over a semester. The key takeaway was the pronounced correlation between improved academic scores and consistent sleep quality and duration in the weeks preceding exams. Additionally, the research delved into gender differences in the context of sleep and academic outcomes.


The study emphatically emphasizes the significant role of sleep in academic success, establishing that sleep metrics influence a remarkable 24.44% variance in academic outcomes. Unlike prior studies, the emphasis here is on consistent sleep throughout the content learning period rather than just the eve of the assessment.

Gender-based findings also emerged as a crucial segment, revealing that improved sleep habits might level the academic playing field between genders.

Methods Summary

With a volunteer pool of 100 students, 88 were finalized for the study, primarily freshmen. The research design integrated a blend of biometric data collection via Fitbit devices and academic assessments.

The academic evaluations encompassed quizzes, midterms, and a final exam, while sleep data, such as duration and quality, was comprehensively recorded. Rigorous procedural controls and explicit participant guidelines underscored the methodological approach, ensuring the integrity of the results.

Reference this article:

Practical Psychology. (2023, October). Forget Cramming, Start Dreaming! How Sleep Consistency Affects College Grades. Retrieved from

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